Electrical connectors are used in a variety of fields. The present invention particularly relates to radio frequency (RF) connectors, although the features of the invention are equally applicable to other connectors. A conventional BNC-type RF connector comprises a plug which mates with a corresponding jack. More recently, smaller versions of the conventional BNC connector have been developed. The mechanical features and function of these are ultimately the same as the conventional BNC connector.
U.S. Pat. No. 7,338,305 discloses a known BNC connector, which is illustrated in FIG. 1.
The jack 1 comprises a cylindrical housing 2 defining a central electrical socket 3 having an electrical contact. A pair of lugs 4 extend radially from the cylindrical housing 2, spaced 180 degrees apart. Conventionally, the jack 1 is mounted to a surface (not shown), such as a PCB.
The plug 5 comprises a cylindrical body 6 having a central pin contact within the body 6 (not shown). A ferrule 7 extends from the body, to which a cable is connected in use. When securing a cable to the plug 5, a length of the outer plastic sheath of the cable is first removed, which exposes a woven shield layer beneath. A smaller length of the shield layer is then removed to expose the dielectric insulator core. Finally, a smaller length of the insulator core is then removed to expose the core conductor of the cable. The conductor is inserted into the body 6 of the plug 5 which makes an electrical connection with the contact of the plug 5. The shield layer is typically then electrically secured to the outer surface of the ferrule 7. Finally, a metal cover is then crimped around the end of the cable, to protect the connection and prevent damage. Additionally, a plastic cover may be heat-shrunk around the end of the cable.
The plug 5 further comprises a rotatable sleeve 8 at the axial end which connects to the jack 1, remote from the ferrule 7. The sleeve comprises two bayonet ‘J-shaped’ slots 9. A resilient element between the body 6 and the sleeve 8 urges the sleeve 8 in an axial direction relative to the body 6, as described below.
To connect the plug 5 to the jack 1, a user grips the sleeve 8 of the plug 5 with the ends of their thumb and index finger and aligns an entry portion 10 of each bayonet slot 9 of the plug 5 with the respective lugs 4 of the jack 1. The user then pushes the plug 5 towards the jack 1 such that the pin contact of the plug 5 is received in the socket 3 of the jack 1, to form an electrical connection with the electrical contact in the socket 3. At the same time, each lug 4 is received in the entry portion 10 of the respective bayonet slot 9. Still gripping the sleeve 8, the user then pushes the sleeve 8 further towards the jack 1, overcoming the bias of the resilient element, thus allowing the sleeve 8 to translate with respect to the body 6. Maintaining this force and continuing to grip the sleeve 8, the user then rotates the sleeve 8 relative to the jack 1. The lug 4 thus translates through the bayonet slot 9. When the lugs 4 contact the end of the bayonet slot 9, the user then releases the axial force. The bias of the resilient element serves to urge the lugs 4 against a terminal portion 11 of the bayonet slot 9, ensuring a positive connection and avoiding inadvertent release of the plug 5 from the jack 1.
Similarly, when removing the plug 5 from the jack 1, the user grips the sleeve 8, applies a force towards the jack 1, against the bias force, then rotates the sleeve 8 and removes the plug 5 from the jack 1.
The method of connection and removal described above is conventional.
It is common to arrange a plurality of jacks 1 across a surface, in close proximity to one another, typically in a grid pattern. When connecting a plurality of plugs 5 to the jacks 1, the plugs 5 will likewise be in close proximity to one another. Once a plurality of plugs 5 are attached to the jacks 1, the removal of a single plug 5, particularly in the centre of the grid array, requires a user to be able to achieve purchase on the sleeve 8 of that plug 5. Given the proximity to other plugs 5, achieving adequate purchase to subsequently rotate the sleeve 8 can be difficult. Similar problems are encountered when securing a plug 5 to a jack 1 in close proximity to other plugs 5.
The problems with removal and installation of plugs are even more acute with smaller BNC plugs and jacks.